Why Panel Climate Control Fails More Often on the Drawing Than in the Field Temperature–humidity controllers look simple, but many problems start at the selection stage: SCADA needs data, but the device has no RS-485 . The cabinet needs separate heater and fan control , but there is only one output contact . A high-humidity panel gets only temperature control, so condensation alarms never stop . Two sensor points are required (top/bottom, two zones), but the controller on